The comparisons started, at least in part, with a column in The Wall Street Journal by Peggy Noonan, a former speechwriter for Ronald Reagan and one of the true poets of American politics.

"Barack Obama, with his elegance and verbal fluency, really did seem like that great and famous political figure from his home state of Illinois -- Adlai Stevenson, who was not at all hungry, not at all mean, and operated at a step removed from the grubby game. Mr. Obama is like someone who would write in his diaries, 'I shall point out Estes Kefauver's manifold inconsistencies, then to luncheon with Arthur and Marietta.'"

The next day, you could read a similar theme on the Huffingtonpost.com: "[A]s things look now, Barack Obama is running an Adlai Stevenson campaign." Slate followed a day later: "[A] more apt precedent, then, is the rhetoric of a different Democratic standard-bearer from the past -- Adlai Stevenson."

And before you know it, a short time thereafter, Karl Rove himself weighed in on C-SPAN that he too saw the comparison as apt: "Someone characterized Obama to me as another Adlai Stevenson, and I think that's probably accurate."

To think, some call Washington an echo chamber.

So let's start with the obvious. Both men are from Illinois. Both served in Springfield. Both were excellent writers. Both delivered a fine, soaring speech. Both attracted the high-minded, the highly educated and the affluent.

A woman once famously approached Stevenson during one of his two losing presidential campaigns and told him that he had the support of "every thinking American." To which Stevenson famously deadpanned, "Thank you, ma'am, but I need a majority."

One person might be in a better position than most others to assess the validity of the comparison to the two orators from Illinois. That would be Adlai Stevenson III, the former U.S. senator from Illinois and two-time (unsuccessful) Democratic candidate for governor.

His first reaction was bemusement. "Too smart to be president," he said of Obama as if he had heard that one somewhere before.

But that's where the similarities largely end.

"There's no comparison between my father and Obama nor between the politics that he represented and the politics of today," Stevenson said. "[My father] wouldn't be possible today. This is a two-year, plus, money-raising and marketing process that few people fit to be president could survive. It costs millions."

This is shaping up as the most drawn-out presidential primary season in history. Aldai Stevenson II entered exactly zero primaries in 1952, leaving those largely ceremonial contests to the aforementioned Kefauver.

"He began his campaign at the convention with no money, no program and no staff and he won hearts and minds the world over," Stevenson said.

"In my father's politics you didn't have to win, you had to serve. You owed the people the truth. What won was more important than who won."

That is not exactly how this campaign is playing out. Indeed, in many ways, it's the inverse: small solutions to big problems. Democrats are mostly hewing to an agenda largely unchanged since 1992; Republicans since perhaps 1980.

The loss of politicians like Stevenson in many ways marked the beginning of the end of the Big Idea in presidential politics.

"All the great Democratic presidents and candidates had a vision and an agenda," Stevenson said. "The New Freedom of Wilson. The New Deal of Roosevelt. Gov. Stevenson's New America was the foundation for the New Frontier and the Great Society. Where are those today in either party?"

Indeed, rather than decry the era of the smoke-filled room, where power brokers determined the nominee more than regular voters, Stevenson sees something to celebrate.

"FDR would not be possible going from state to state, pandering to every local interest, shaking the tambourine as you go," Stevenson said. "Woodrow Wilson, either.

"Every great president was chosen by politicians in conventions, assembled for a very serious business. They knew the candidates, the demands for public office and they knew something of the issues. Mea culpa, I was one of the reformers on the McGovern Commission [which essentially gave voters the primary-driven process we have today, rendering the conventions a scripted ceremony].

"I think in trying to make the process more open and more democratic, we made it plutocratic," Stevenson said. "And we really cheapened the discourse. My father could take out half-hour blocks of time on national television for eloquent, substantive speeches ... and five minutes of time for face-to-face talks." Which is not to say that Stevenson was all self-serious. One of his rhetorical gifts was his sense of spontaneous humor.

Republicans forever changed the process by airing TV commercials in 1952, a day that lived in infamy with the Stevenson clan. Stevenson's father said, "The presidency isn't a contest between Palmolive and Colgate."

He had a point.

So it is amusing from afar to see the name Stevenson invoked in presidential politics, though not necessarily as a compliment.

Of Obama, Stevenson said, "He may be over-qualified. He's highly literate. He's intelligent and that somehow renders him unfit. Maybe unfit to win, but not unfit to govern."